Windows 7: Sapphire Radeon HD 6950 not recognized as Audio Device by Win7 64bit

So, I am trying to cut down on remotes and cable clutter, and decided to switch over to using my Radeon HD 6950's sound abilities and go to a single HDMI cable connected to my Yamaha RX-V671, which is then connected to my HDTV. Sounded easy, I should have known better...

Anyway, I hooked everything up, disabled (and removed, if possible) all other audio devices including Realtek on-board sound and an old Soundblaster PCI-e sound card, and booted the system up only to find that Windows 7 64-Bit does not recognize the audio capabilities of my video card. Under the "playback" tab of my sound menu, there is nothing listed and all "show" options are enabled, there's just nothing to see in the menu.

System-wise, I'm running an older Gigabyte MB, 790fx, with a Phenom quad-core. 8gb ram, and nothing else of note I believe. The OS is, as mentioned, Windows 7, 64-bit.

All drivers have been updated... Oh, a bonus on this one... I tried to install the specific AMD HD Audio Driver for 64-bit systems from the Realtek website (Realtek) and got an error message saying something to the tune of "no supported drivers in this package".

I have been trying to figure this mess out for about 6 hours, with no luck. I hope someone can help, and thanks in advance!